Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2003-07-09
2004-10-19
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S355000, C528S272000, C528S343000
Reexamination Certificate
active
06806346
ABSTRACT:
FIELD OF THE INVENTION
Mixtures of cyclic ester oligomers derived from different dicarboxylic acids and/or different diols may be copolymerized to form copolyesters. Depending upon the mixture of cyclic ester oligomers chosen, the properties of the resulting copolyester may be tailored for specific applications.
TECHNICAL BACKGROUND
Cyclic ester oligomers (CEOs) have been known for a long time (see for instance U.S. Pat. No. 2,020,298), and it is well known that they can be polymerized to form polyesters (LPEs), see for instance U.S. Pat. Nos. 5,466,744 and 5,661,214 and references cited therein. The CEOs have been of particular interest because they themselves, when melted, are low viscosity liquids which may be readily polymerized to higher molecular weight polymers, for instance in a process similar to reaction injection molding which is commonly used for thermoset resins.
CEOs are typically compounds of the formula
wherein R
1
and R
2
are each independently hydrocarbylene or substituted hydrocarbylene, and m is an integer of 1 or more. Herein when m is 1, the compound is a unimer, when m is 2 the compound is a dimer, when m is three the compound is a trimer, etc. Copolyesters (CPEs) are formed when a mixture of two or more compounds (I) wherein R
1
and/or R
2
are varied is polymerized to form a CPE which contains R
1
and R
2
groups derived from the compounds (I) which were in the mixture of CEOs. Because the resulting CPE are copolymers, some of their properties are typically different than the properties of their “constituent” “homopolyesters”. For example the melting point and/or glass transition temperature and/or heat of fusion of the CPE will typically be different from the constituent homopolyesters.
Random copolyesters derived from terephthalic acid, 1,4-butanediol and diethylene glycol are known, see for instance U.S. Pat. No. 4,419,507 and N. Lotti, et al., Polymer, vol. 41, p. 5297-5304 (2000). Neither of these references describes copolyesters which are not random.
U.S. Pat. Nos. 5,648,454 and 6,420,047 describe the polymerization of certain CEOs in which some of the individual CEO molecules contain groups (“equivalent” to R
2
herein) derived from different diols. Groups derived from one of the diols are present in small amounts.
SUMMARY OF THE INVENTION
This invention concerns a process for the copolymerization of cyclic ester oligomers, comprising, contacting under ring opening polymerization conditions a mixture of two or more molten chemically different cyclic ester oligomers of the formula
with a catalyst for the ring opening polymerization of cyclic ester oligomers, to form a copolyester, wherein:
R
1
and R
2
are each independently hydrocarbylene or substituted hydrocarbylene; and
m is an integer of 1 or more; and
provided that when every R
1
in each molecule of cyclic ester oligomer is not the same and/or every R
2
in each molecule of cyclic ester oligomer is not the same, at least two of the chemically different cyclic ester oligomers present are at least 15 mole percent to total amount of cyclic ester oligomers present.
Also disclosed herein is a process for encapsulating or coating an object, comprising, contacting said object with a molten mixture of two or more chemically different cyclic ester oligomers and copolymerizing said molten mixture to form a copolyester which encapsulates or coats said object.
Also disclosed is a copolyester with a degree of randomness of about 0.20 to 0.85.
Described herein is a copolyester wherein single repeat unit blocks of that CEO composition are less than 5 mole percent of those units.
DETAILS OF THE INVENTION
Herein certain terms are used and some of them are:
By “chemically different cyclic ester oligomers” is meant that two or more oligomers are derived from different dicarboxylic acids and/or diols. They do not include oligomers that differ only in the value of “m”, that is CEOs which are dimers, trimers, etc., but are derived from the same dicarboxylic acid(s) and diol(s). If a first single CEO is derived from two different dicarboxylic acids and/or two different diols, then a chemically different CEO must be derived from at least one dicarboxylic acid and/or one diol which is not present in the first single CEO.
By hydrocarbylene herein is meant a divalent radical containing only carbon and hydrogen whose (two) free valences are each single bonds to the same or different carbon atoms. Example of hydrocarbylene groups include p-phenylene, m-phenylene and hexamethylene.
By substituted hydrocarbylene herein is meant hydrocarbylene containing one or more heteroatoms other than carbon and hydrogen, for example halogen, oxygen, and nitrogen. The heteroatoms, which by themselves or with other atoms may form “functional groups” should not substantially interfere with any chemical reactions or processes which the composition containing the functional groups is part of. Useful functional groups include ether, keto, chloro, bromo, thioether, and tertiary amino.
The CEOs which are polymerized herein are made by processes which are known, see for instance U.S. Pat. Nos. 5,039,783, 5,214,158, 5,231,161, and 5,321,117. Oftentimes CEOs, for example those derived from a single dicarboxylic acid and single diol, are obtained as mixtures of cyclic molecules which vary [as in (I)] in “m”, the number of “repeat” units in the molecule. The CEOs which are polymerized herein may be cyclics in which m is a single number i.e. the CEO is a (for example) dimer, trimer, etc., or CEOs where m is more than one integer i.e. the CEO is a mixture of (for example) dimer, trimer, etc.
In the chemically different CEOs (for all purposes herein) it is preferred that they are derived from:
(a) A preferred diol is an aliphatic diol, that is a diol in which each hydroxyl group is bound to different alkyl carbon atoms. Other preferred diols include diols of the formula HOCH
2
(CR
3
R
4
)
q
CH
2
OH or HO(CH
2
CH
2
O)
t
H wherein R
3
and R
4
are each independently hydrogen or alkyl, and q is 0 or an integer of 1 to 10, or t is an integer of 2 to 20, more preferably all R
3
and R
4
are hydrogen, and n is 0 or an integer 1 to 4, or t is 2 or 3, and especially preferably n is 0, 1 or 2, or t is 2. Other specific preferred diols include hydroquinone, and bisphenol-A, and combinations thereof.
(b) Preferred dicarboxylic acids (or their derivatives including half-acid esters and diesters) are compounds of the formula HO
2
C(CH
2
)
n
CO
2
H wherein n is an integer of 1 to 10, isophthalic acid, substituted isophthalic acids, terephthalic acid, substituted terephthalic acids, and 2,6-naphthalenedicarboxylic acid, and combinations thereof. More preferred carboxylic acids are terephthalic acid and isophthalic acid, and terephthalic acid is especially preferred. Any combination of preferred dicarboxylic acid and preferred diols (above) may form a preferred CEO.
(c) Specific preferred combinations of dicarboxylic acids and diols include terephthalic acid with diethylene glycol [bis(2-hydroxyethyl)ether], ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol or a mixture thereof, isophthalic acid with diethylene glycol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5pentanediol, and 1,6-hexanediol or a mixture thereof, and succinic and/or adipic acid with one or more compounds of the formula HOCH
2
(CR
3
R
4
)
n
CH
2
OH, wherein R
3
and R
4
are hydrogen or alkyl containing 1 to 4 carbon atoms and n is 0 or an integer of 1 to 10.
A preferred combination of chemically different CEOs for the copolymerization process described herein are any two more the preferred individual CEOs described above. A particularly preferred combination of chemically different CEOs is: a CEO derived from terephthalic acid with any one of ethylene glycol, 1,3-propanediol, or 1,4-butanediol with a CEO derived from terephthalic or isophthalic acid with any one of HO(CH
2
CH
2
O)
t
H wherein t is 2, 3 or 4, more preferably 2; and a CEO derived from terephthalic acid with any one of ethylene glycol, 1,3-propanediol, or 1
E. I. du Pont de Nemours and Company
Truong Duc
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